1. Field of the Invention
The present invention relates to a disk changer and more particularly a disk changer which moves a disk holding tray, i.e., a disk tray, up to a predetermined rotational position.
2. Description of the Prior Art
As a conventional disk changer there is known a disk changer disclosed in Japanese Published Unexamined Patent Application No. Hei 9-147468. On a chassis of this disk changer is placed a disk-shaped tray, i.e., a disk tray, which is mounted on a rotating shaft of a spindle motor. Plural disks are received circumferentially on an upper surface of the disk tray.
In this construction, when the spindle motor operates, the disk tray rotates with a driving force which is transmitted thereto from the spindle motor, causing any of the disks received in the upper surface thereof to rotate up to a position opposed to a pickup, thereby permitting the disk to be held by a chuck arm.
The above conventional disk changer involves the following problem.
In a disk changer, a disk tray is usually formed by molding resin in a large-sized disk shape so as to permit plural disks to be received thereon. Consequently, a rotational surface of the disk tray is apt to be undulated in the molding.
With such undulation, when the disk tray is to be supported at a peripheral edge of its lower surface or thereabouts by means of plural rollers arranged on an upper surface of the chassis, there occur variations in the state of abutment between the lower surface of the disk tray and each roller, thus making it impossible to impart a uniform rotating torque to the disk tray. Unevenness in rotation may result.
The present invention has been accomplished in view of the above-mentioned problem and it is an object of the invention to provide a disk changer which can stabilize a rotating torque of a disk tray and thereby eliminate unevenness in rotation.
According to the present invention, for achieving the above object, there is provided a disk changer comprising:
a slide tray made of resin in a square plate shape, the slide tray having a circular recess and rollers and being installed in a manner capable of being drawn out from a cabinet body, the circular recess being formed in an upper surface of the slide tray so as to face upward around a cylindrical support shaft, the rollers being arranged at equal intervals in three positions on a circumference on the upper surface of the slide tray which circumference is centered at the support shaft, while allowing rotating shafts of the rollers to be oriented radially of the circular recess;
a disk tray made of resin, the disk tray having a tray axial bore formed axially thereof and into which the support shaft is inserted rotatably, an annular recess formed in an upper surface of the disk tray in a surrounding relation to the tray axial bore, disk receptacle portions formed circumferentially at equal intervals in five positions on the upper surface of the disk tray, and a ring gear disposed on a circumference on a lower surface of the disk tray which circumference is centered at the tray axial bore, the ring gear being engageable with a driving gear, the disk tray being placed in the circular recess of the slide tray while being supported at a peripheral edge of its lower surface and thereabouts by means of the rollers; and
a chuck arm made of resin, the chuck arm having an arm axial bore formed on one end side thereof and into which the support shaft is inserted, an annular recess formed in a lower surface of the chuck arm in a surrounding relation to the arm axial bore, the annular recess being able to confront the annular recess formed in the disk tray, and a through hole formed on an opposite side of the chuck arm and able to confront a central part of each of the disk receptacle portions, the chuck arm being mounted to the support shaft while allowing a spring to be accommodated within a space which is formed by making the annular recesses confront each other, the spring being disposed so that it can expand and contract axially of the support shaft.
In the present invention constructed as above, the slide tray made of resin in a square plate shape and provided in an upper surface thereof with a circular recess which faces upward around the cylindrical support shaft, is disposed so that it can be drawn out from a cabinet body.
In the slide tray made of resin, rollers having rotating shafts oriented radially of the circular recess are arranged at equal intervals in three positions on a circumference which is centered at the support shaft. The resinous disk tray with the support shaft inserted into the tray axial bore is placed on the circular recess while being supported at the peripheral edge of its lower surface and thereabouts by the rollers. Disks are received respectively within the disk receptacle portions which are formed at equal intervals in five circumferential positions on the upper surface of the disk tray. A driving gear is brought into mesh with the ring gear which is disposed on a circumference on the lower surface of the disk tray which circumference is centered at the tray axial bore, and the disk tray is rotated with a driving force which is transmitted to the disk tray from a drive motor through the driving gear.
The chuck arm made of resin is mounted to the support shaft while inserting the support shaft into the arm axial bore. At this time, a spring adapted to expand and contract axially of the support shaft is received within a space which is defined by the annular, or ring-shaped, recess formed in the upper surface of the disk tray in a surrounding relation to the support shaft and the annular, or ring-shaped, recess formed in the lower surface of the chuck arm in a surrounding relation to the arm axial bore. The through hole formed on the opposite end side of the chuck arm comes into opposition to a central part of the disk accommodated within each disk receptacle portion to chuck the disk.
Thus, since the disk tray made of resin is supported from below at the peripheral edge of its lower surface and thereabouts by means of the rollers and its axis and the vicinity thereof are pressed down with the biasing force of the foregoing spring, the disk tray as a whole assumes a downwardly warped state and absorbs undulation, so that there is attained a uniform abutment of its lower surface with the rollers and hence the rotating torque is stabilized.
Thus, according to the present invention it is possible to realize, in terms of a concrete construction, a disk changer which can stabilize the rotating torque of the disk tray and thereby eliminate unevenness in rotation.
Although the present invention is realized as a disk changer having a concrete construction, such a construction is a mere example and the technique contemplated by the invention can be grasped over a wide scope.
More specifically, the present invention may have a construction comprising a disk tray which receives plural disks on a surface thereof, a drive mechanism for rotating the disk tray, a chassis provided with plural rollers which support the disk tray rotatably on a back side of the same tray, and a support shaft structure which urges the disk tray toward the chassis while supporting the disk tray rotatably about an axis of the disk tray relative to the chassis.
In this construction, plural rollers disposed on the chassis support the back side of the disk tray rotatably, the disk tray being rotated by a drive mechanism. On the surface side of the disk tray there can be accommodated plural disks.
The support shaft structure urges the disk tray toward the chassis while supporting the disk tray rotatably about the axis of the same tray with respect to the chassis. Therefore, when the disk tray is displaced in the vicinity of its axis toward the chassis, it assumes a warped state as a whole. As a result, undulation of the disk tray is eliminated and the state of abutment thereof with the portion which supports the same tray becomes uniform, thus stabilizing the rotating torque of the disk tray during rotation of the tray.
From the standpoint of permitting the occurrence of undulation, it is optional whether the disk tray is formed by molding resin or by metal working. No limitation is placed on the material thereof.
Likewise, it is optional whether this disk changer is to be used while orienting the disk tray in the horizontal direction or in the vertical direction. In which direction the disk tray is to be oriented in use is not specially limited.
Thus, according to the above construction it is possible to provide a disk changer which can stabilize the rotating torque of the disk tray to eliminate unevenness in rotation.
As an example of a concrete construction of the support shaft structure as referred to herein there may be adopted a construction provided with a spring, the spring being able to expand and contract in the axial direction of the disk tray, one end of the spring being spaced a predetermined distance from the chassis and positioned there, an opposite end of the spring being pressed against a vicinity of the disk tray axis from the side opposite to the chassis.
In this construction, one end of the spring disposed so as to expand and contract axially the disk tray is positioned while being spaced a predetermined distance from the chassis. On the other hand, the opposite end of the spring is pressed against a vicinity of the disk tray axis from the side opposite to the chassis.
Thus, the spring urges the disk tray in the vicinity of the tray axis toward the chassis, causing the disk tray to be warped as a whole, thereby eliminating undulation of the disk tray and stabilizing the rotating torque of the same tray.
The use of such a spring in the support shaft structure is advantageous in that the biasing force of the spring can be changed easily by adjusting the spring constant or by adjusting the state of expansion and contraction when installed. But this construction is a mere example and there also may be used a resinous member having elasticity.
The support shaft structure can thus be realized by a concrete construction.
As an example of construction for eliminating undulation of the disk tray effectively when the vicinity of the disk tray axis is urged toward the chassis, there may be adopted a construction wherein the disk tray is formed by molding while the vicinity of the disk tray axis is displaced away from the chassis, causing the whole of disk tray to be warped in an arcuate sectional shape.
According to this construction, the disk tray is formed by molding resin while it is displaced away from the chassis in the vicinity of its axis and is thereby warped in an arcuate sectional shape as a whole, so when the vicinity of the disk tray axis is urged toward the chassis by the support shaft structure, the warping direction of the disk tray is inverted into a downwardly convex warp and in this state the disk tray is installed.
Consequently, the entire shape of the tray can be greatly changed while eliminating undulation of the tray not only during the period from a generally planar state until a downwardly convex state but also during the period from an upwardly convex state until a generally planar state, thus making it possible to eliminate undulation of the disk tray in a more positive manner.
Further, as an example of construction for warping the disk tray efficiently when the vicinity of the disk tray axis is urged toward the chassis, there may be adopted a construction wherein the chassis portion opposed to the vicinity of the disk tray axis is depressed as a recess in a direction away from the disk tray.
According to this construction, when the vicinity of the disk tray axis is urged toward the chassis by the support shaft structure, the disk tray is pressed toward the recess formed by depressing the chassis portion opposed to the vicinity of the tray axis in a direction away from the disk tray. As a result, the vicinity of the disk tray axis becomes easier to be displaced toward the chassis and hence it becomes easier to eliminate undulation of the disk tray.
Thus, undulation of the disk tray can be eliminated easily.